migration/multifd-zstd.c

   1 /*
   2  * Multifd zlib compression implementation
   3  *
   4  * Copyright (c) 2020 Red Hat Inc
   5  *
   6  * Authors:
   7  *  Juan Quintela <quintela@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include <zstd.h>
  15 #include "qemu/rcu.h"
  16 #include "exec/ramblock.h"
  17 #include "exec/target_page.h"
  18 #include "qapi/error.h"
  19 #include "migration.h"
  20 #include "trace.h"
  21 #include "options.h"
  22 #include "multifd.h"
  23
  24 struct zstd_data {
  25     /* stream for compression */
  26     ZSTD_CStream *zcs;
  27     /* stream for decompression */
  28     ZSTD_DStream *zds;
  29     /* buffers */
  30     ZSTD_inBuffer in;
  31     ZSTD_outBuffer out;
  32     /* compressed buffer */
  33     uint8_t *zbuff;
  34     /* size of compressed buffer */
  35     uint32_t zbuff_len;
  36 };
  37
  38 /* Multifd zstd compression */
  39
  40 /**
  41  * zstd_send_setup: setup send side
  42  *
  43  * Setup each channel with zstd compression.
  44  *
  45  * Returns 0 for success or -1 for error
  46  *
  47  * @p: Params for the channel that we are using
  48  * @errp: pointer to an error
  49  */
  50 static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
  51 {
  52     struct zstd_data *z = g_new0(struct zstd_data, 1);
  53     int res;
  54
  55     p->data = z;
  56     z->zcs = ZSTD_createCStream();
  57     if (!z->zcs) {
  58         g_free(z);
  59         error_setg(errp, "multifd %u: zstd createCStream failed", p->id);
  60         return -1;
  61     }
  62
  63     res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level());
  64     if (ZSTD_isError(res)) {
  65         ZSTD_freeCStream(z->zcs);
  66         g_free(z);
  67         error_setg(errp, "multifd %u: initCStream failed with error %s",
  68                    p->id, ZSTD_getErrorName(res));
  69         return -1;
  70     }
  71     /* This is the maximum size of the compressed buffer */
  72     z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE);
  73     z->zbuff = g_try_malloc(z->zbuff_len);
  74     if (!z->zbuff) {
  75         ZSTD_freeCStream(z->zcs);
  76         g_free(z);
  77         error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
  78         return -1;
  79     }
  80     return 0;
  81 }
  82
  83 /**
  84  * zstd_send_cleanup: cleanup send side
  85  *
  86  * Close the channel and return memory.
  87  *
  88  * @p: Params for the channel that we are using
  89  * @errp: pointer to an error
  90  */
  91 static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
  92 {
  93     struct zstd_data *z = p->data;
  94
  95     ZSTD_freeCStream(z->zcs);
  96     z->zcs = NULL;
  97     g_free(z->zbuff);
  98     z->zbuff = NULL;
  99     g_free(p->data);
 100     p->data = NULL;
 101 }
 102
 103 /**
 104  * zstd_send_prepare: prepare date to be able to send
 105  *
 106  * Create a compressed buffer with all the pages that we are going to
 107  * send.
 108  *
 109  * Returns 0 for success or -1 for error
 110  *
 111  * @p: Params for the channel that we are using
 112  * @errp: pointer to an error
 113  */
 114 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
 115 {
 116     MultiFDPages_t *pages = p->pages;
 117     struct zstd_data *z = p->data;
 118     int ret;
 119     uint32_t i;
 120
 121     multifd_send_prepare_header(p);
 122
 123     z->out.dst = z->zbuff;
 124     z->out.size = z->zbuff_len;
 125     z->out.pos = 0;
 126
 127     for (i = 0; i < pages->num; i++) {
 128         ZSTD_EndDirective flush = ZSTD_e_continue;
 129
 130         if (i == pages->num - 1) {
 131             flush = ZSTD_e_flush;
 132         }
 133         z->in.src = p->pages->block->host + pages->offset[i];
 134         z->in.size = p->page_size;
 135         z->in.pos = 0;
 136
 137         /*
 138          * Welcome to compressStream2 semantics
 139          *
 140          * We need to loop while:
 141          * - return is > 0
 142          * - there is input available
 143          * - there is output space free
 144          */
 145         do {
 146             ret = ZSTD_compressStream2(z->zcs, &z->out, &z->in, flush);
 147         } while (ret > 0 && (z->in.size - z->in.pos > 0)
 148                          && (z->out.size - z->out.pos > 0));
 149         if (ret > 0 && (z->in.size - z->in.pos > 0)) {
 150             error_setg(errp, "multifd %u: compressStream buffer too small",
 151                        p->id);
 152             return -1;
 153         }
 154         if (ZSTD_isError(ret)) {
 155             error_setg(errp, "multifd %u: compressStream error %s",
 156                        p->id, ZSTD_getErrorName(ret));
 157             return -1;
 158         }
 159     }
 160     p->iov[p->iovs_num].iov_base = z->zbuff;
 161     p->iov[p->iovs_num].iov_len = z->out.pos;
 162     p->iovs_num++;
 163     p->next_packet_size = z->out.pos;
 164     p->flags |= MULTIFD_FLAG_ZSTD;
 165
 166     multifd_send_fill_packet(p);
 167
 168     return 0;
 169 }
 170
 171 /**
 172  * zstd_recv_setup: setup receive side
 173  *
 174  * Create the compressed channel and buffer.
 175  *
 176  * Returns 0 for success or -1 for error
 177  *
 178  * @p: Params for the channel that we are using
 179  * @errp: pointer to an error
 180  */
 181 static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
 182 {
 183     struct zstd_data *z = g_new0(struct zstd_data, 1);
 184     int ret;
 185
 186     p->data = z;
 187     z->zds = ZSTD_createDStream();
 188     if (!z->zds) {
 189         g_free(z);
 190         error_setg(errp, "multifd %u: zstd createDStream failed", p->id);
 191         return -1;
 192     }
 193
 194     ret = ZSTD_initDStream(z->zds);
 195     if (ZSTD_isError(ret)) {
 196         ZSTD_freeDStream(z->zds);
 197         g_free(z);
 198         error_setg(errp, "multifd %u: initDStream failed with error %s",
 199                    p->id, ZSTD_getErrorName(ret));
 200         return -1;
 201     }
 202
 203     /* To be safe, we reserve twice the size of the packet */
 204     z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
 205     z->zbuff = g_try_malloc(z->zbuff_len);
 206     if (!z->zbuff) {
 207         ZSTD_freeDStream(z->zds);
 208         g_free(z);
 209         error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
 210         return -1;
 211     }
 212     return 0;
 213 }
 214
 215 /**
 216  * zstd_recv_cleanup: setup receive side
 217  *
 218  * For no compression this function does nothing.
 219  *
 220  * @p: Params for the channel that we are using
 221  */
 222 static void zstd_recv_cleanup(MultiFDRecvParams *p)
 223 {
 224     struct zstd_data *z = p->data;
 225
 226     ZSTD_freeDStream(z->zds);
 227     z->zds = NULL;
 228     g_free(z->zbuff);
 229     z->zbuff = NULL;
 230     g_free(p->data);
 231     p->data = NULL;
 232 }
 233
 234 /**
 235  * zstd_recv_pages: read the data from the channel into actual pages
 236  *
 237  * Read the compressed buffer, and uncompress it into the actual
 238  * pages.
 239  *
 240  * Returns 0 for success or -1 for error
 241  *
 242  * @p: Params for the channel that we are using
 243  * @errp: pointer to an error
 244  */
 245 static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
 246 {
 247     uint32_t in_size = p->next_packet_size;
 248     uint32_t out_size = 0;
 249     uint32_t expected_size = p->normal_num * p->page_size;
 250     uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
 251     struct zstd_data *z = p->data;
 252     int ret;
 253     int i;
 254
 255     if (flags != MULTIFD_FLAG_ZSTD) {
 256         error_setg(errp, "multifd %u: flags received %x flags expected %x",
 257                    p->id, flags, MULTIFD_FLAG_ZSTD);
 258         return -1;
 259     }
 260     ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
 261
 262     if (ret != 0) {
 263         return ret;
 264     }
 265
 266     z->in.src = z->zbuff;
 267     z->in.size = in_size;
 268     z->in.pos = 0;
 269
 270     for (i = 0; i < p->normal_num; i++) {
 271         z->out.dst = p->host + p->normal[i];
 272         z->out.size = p->page_size;
 273         z->out.pos = 0;
 274
 275         /*
 276          * Welcome to decompressStream semantics
 277          *
 278          * We need to loop while:
 279          * - return is > 0
 280          * - there is input available
 281          * - we haven't put out a full page
 282          */
 283         do {
 284             ret = ZSTD_decompressStream(z->zds, &z->out, &z->in);
 285         } while (ret > 0 && (z->in.size - z->in.pos > 0)
 286                          && (z->out.pos < p->page_size));
 287         if (ret > 0 && (z->out.pos < p->page_size)) {
 288             error_setg(errp, "multifd %u: decompressStream buffer too small",
 289                        p->id);
 290             return -1;
 291         }
 292         if (ZSTD_isError(ret)) {
 293             error_setg(errp, "multifd %u: decompressStream returned %s",
 294                        p->id, ZSTD_getErrorName(ret));
 295             return ret;
 296         }
 297         out_size += z->out.pos;
 298     }
 299     if (out_size != expected_size) {
 300         error_setg(errp, "multifd %u: packet size received %u size expected %u",
 301                    p->id, out_size, expected_size);
 302         return -1;
 303     }
 304     return 0;
 305 }
 306
 307 static MultiFDMethods multifd_zstd_ops = {
 308     .send_setup = zstd_send_setup,
 309     .send_cleanup = zstd_send_cleanup,
 310     .send_prepare = zstd_send_prepare,
 311     .recv_setup = zstd_recv_setup,
 312     .recv_cleanup = zstd_recv_cleanup,
 313     .recv_pages = zstd_recv_pages
 314 };
 315
 316 static void multifd_zstd_register(void)
 317 {
 318     multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops);
 319 }
 320
 321 migration_init(multifd_zstd_register);